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Garden walls are often good-looking, but that fact often disguises a more important purpose: they are holding soil in place. If your garden wall has begun to fail due to erosion from underneath it, the stability of your entire yard may be at risk. Use these tricks to minimize erosion damage, starting from the wall’s initial construction through to planting.

Start With Construction

The best way to keep water from causing erosion when it flows out from underneath a wall is to build drainage mechanisms into the wall itself. This includes using drainage cloth against the wall to keep it stable, building it on a base of compacted sand or gravel rather than soil, and placing sand in a wedge between the wall and the backfill. You can also place small pipes that run from the sand layer on the bed side of the wall underneath the stones to the other side so that they can transport water past the vulnerable soil area.

Build Multiple Walls

If the main water problem on your property is that slopes higher up are bringing water down toward your wall, then consider building multiple walls up the slope in a terraced fashion. This will help keep water in level beds up above, where it can be used to grow other plants that will in turn control erosion with their roots. Keep in mind that the steeper your slope is, the closer your terraces will need to be, and therefore, the more you will have.

Reroute Water

Perhaps the simplest way to keep large amounts of water from seeping out underneath a wall is to reroute extra water that flows over the surface of the bed or down slopes above. You can do this with drainage channels cut into the landscape, rather than simply allowing water to run across the face of the slope or bed. When you irrigate your garden near the wall, use soaker hoses or drip lines that add moisture slowly to the landscape so it has time to soak in. This will prevent it from washing to a single point in the yard where it can undermine your wall or other structures.

Use Groundcovers

Groundcovers help to keep the soil in place by anchoring it with their roots. Not only that, but they use water, so they waylay some of it as it comes through their planting zones. Consider a grass like northern sea oats, 2 to 5 feet tall and hardy in U.S. Department of Agriculture plant hardiness zones 3 though 8. Or try a fern like ebony spleenwort (Asplenium platyneuron), growing to a full height of a foot and hardy in the same USDA zones.